This tool checks your computer for infection by specific, prevalent malicious software (including Blaster, Sasser, and Mydoom) and helps to remove the infection if it is found. Microsoft will release an updated version of this tool on the second Tuesday of each month.

Generally, a download manager enables downloading of large files or multiples files in one session.Many web browsers, such as Internet Explorer 9, include a download manager.Stand-alone download managers also are available, including the Microsoft Download Manager.

if you do not have a download manager installed, and still want to download the file(s) you've chosen, please note:

You may not be able to download multiple files at the same time.In this case, you will have to download the files individually.(You would have the opportunity to download individual files on the "Thank you for downloading" page after completing your download.)

Files larger than 1 GB may take much longer to download and might not download correctly.

You might not be able to pause the active downloads or resume downloads that have failed.

The Microsoft Download Manager solves these potential problems.It gives you the ability to download multiple files at one time and download large files quickly and reliably.It also allows you to suspend active downloads and resume downloads that have failed.

Microsoft .NET Framework 3.5 Service Pack 1 is a full cumulative update that contains many new features building incrementally upon .NET Framework 2.0, 3.0, 3.5, and includes cumulative servicing updates to the .NET Framework 2.0 and .NET Framework 3.0 subcomponents.

.NET Framework version 3.5 Service Pack 1 provides the following new features and improvements:

ASP.NET Dynamic Data, which provides a rich scaffolding framework that enables rapid data driven development without writing code, and a new addition to ASP.NET AJAX that provides support for managing browser history (back button support). For more information, see What’s New in ASP.NET and Web Development.

Core improvements to the CLR (common language runtime) that include better layout of .NET Framework native images, opting out of strong-name verification for fully trusted assemblies, improved application startup performance, better generated code that improves end-to-end application execution time, and opting managed code to run in ASLR (Address Space Layout Randomization) mode if supported by the operating system. Additionally, managed applications that are opened from network shares have the same behavior as native applications by running with full trust.

Performance improvements to WPF (Windows Presentation Foundation), including a faster startup time and improved performance for Bitmap effects. Additional functionality for WPF includes better support for line of business applications, native splash screen support, DirectX pixel shader support, and the new WebBrowser control.

ClickOnce application publishers can decide to opt out of signing and hashing as appropriate for their scenarios, developers can programmatically install ClickOnce applications that display a customized branding, and ClickOnce error dialog boxes support links to application-specific support sites on the Web.

The Entity Framework is an evolution of the existing suite of ADO.NET data access technologies. The Entity Framework enables developers to program against relational databases in according to application-specific domain models instead of the underlying database models. For more information, see Getting Started with the Entity Framework. The Entity Framework introduces some additional features, including support for new SQL Server 2008 types, default graph serialization of Entities, and the Entity Data Source. This release of the Entity Framework supports the new date and file stream capabilities in SQL Server 2008. The graph serialization work helps developers who want to build Windows Communication Foundation (WCF) services that model full graphs as data contracts. The Entity Data Source provides a traditional data source experience for ASP.NET Web application builders who want to work with the Entity Framework.

LINQ to SQL includes new support for the new date and file stream capabilities in SQL Server 2008.

The ADO.NET Data Services Framework consists of a combination of patterns and libraries, which enable data to be exposed as a flexible REST (Representational State Transfer)-based data service that can be consumed by Web clients in a corporate network or across the Internet. The ADO.NET Data Services Framework makes data service creation over any data source. A conceptual view model of the underlying storage schema can easily be exposed through rich integration with the ADO.NET Entity Framework. Services created by using the ADO.NET Data Services Framework, and also compatible Windows Live (dev.live.com) services, can be easily accessed from any platform. For client applications that are running on Microsoft platforms, a set of client libraries are provided to make interaction with data services simple. For example, .NET Framework-based clients can use LINQ to query data services and a simple .NET Framework object layer to update data in the service.

Windows Communication Foundation now makes the DataContract Serializer easier to use by providing improved interoperability support, enhancing the debugging experience in partial trust scenarios, and extending syndication protocol support for wider usage in Web 2.0 applications.

The .NET Framework Data Provider for SQL Server (SqlClient) adds new support for file stream and sparse column capabilities in SQL Server 2008.

Important: Please read the release notes for known issues before you install the service pack. Make sure you have the latest service pack and critical updates for the version of Windows on the computer. To look for recent updates, visit Windows Update. In addition, make sure you have Windows Installer 3.1 installed before you install this service pack.

Click the Download button on this page to start the download

To save the download to your computer for installation at a later time, click Save.

IMPORTANT: After installing the .NET Framework 3.5 SP1 package (either the bootstrapper or the full package) you should immediately install the update KB959209 to address a set of known application compatibility issues.
In addition, on Windows Vista x64 and Windows Server 2008 x64, install the update KB967190 to address a file association issue for XPS documents.

The following information may be relevant for administrators performing deployments of the .NET Framework on to operating systems using non-English locales. This package does not contain localized resources for non-English locales. By default, it downloads and installs the language pack that matches the language of the customer’s operating system. This may not be desired behavior when managing deployments of the .NET Framework. To avoid the automatic download use the following command:

Popular Downloads

The Microsoft .NET Framework 4 web installer package downloads and installs the .NET Framework components required to run on the target machine architecture and OS. An Internet connection is required during the installation. .NET Framework 4 is required to run and develop applications to target the .NET Framework 4.

The Microsoft Visual C++ 2010 Redistributable Package installs runtime components of Visual C++ Libraries required to run applications developed with Visual C++ on a computer that does not have Visual C++ 2010 installed.